We Thought There Was One Giraffe Species—But There Are Four


For more than 250 years, there has been one universally accepted species of giraffe: Giraffa camelopardalis. But according to a study of the spotted giant’s DNA published today, September 8, in the journal Current Biology, that one species should actually be several.

This is exciting news, partly because it settles a debate about giraffe identity that’s been taking place for centuries. While Giraffa camelopardalis has enjoyed its seat at the top of the hierarchy since Carl Linnaeus officially described the animal back in 1758, there has been a lot of back and forth about just how many subspecies of giraffe truly exist. Some scientists believe there are 11 subspecies while most others argue there are just nine.

But it turns out they’re all wrong, according to the new study, which says there are actually four species of giraffe and five subspecies.

Axel Janke, a geneticist at Senckenberg Museum and Goethe University in Germany, said he and his coauthors were completely surprised by the findings.

“There is not much known about giraffes,” Janke tells mental_floss. In fact, the world’s tallest animals get far less scientific and conservation attention than other megafauna like lions and elephants.

To remedy this lack of knowledge, study lead author and Giraffe Conservation Fund co-founder Julian Fennessy spent six years sampling 190 giraffes from all over Central and Southern Africa. Thanks to special darts designed to snag a small tissue sample as they puncture an animal’s skin, Fennessy was able to collect noninvasive DNA samples from all nine accepted subspecies of giraffe, which Janke then analyzed against each other. The study represents the most expansive work on giraffe genetics to date.

Once the scientists started looking at the various genomes, they were surprised to find that all of their samples seemed to cluster into four distinct groups, each as different from the other as a polar bear is from a grizzly. Their analysis suggests that the giraffe family would be best described as containing four main species: the southern giraffe (Giraffa giraffa), the Masai giraffe (G. tippelskirchi), the reticulated giraffe (G. reticulata), and the northern giraffe (G. camelopardalis).

Furthermore, the study was able to eliminate some of the subspecies categories by showing that Thornicroft’s giraffe and the Masai giraffe are genetically identical, as are the Rothschild’s giraffe and the Nubian giraffe.

But this is more than some scholarly exercise in giraffe taxonomy.

“This paper is a much-needed wake-up call to save these magnificent animals,” Douglas Cavener, a Penn State geneticist who studies giraffes, tells mental_floss. (Cavener was not involved with the new study.)

Scientists estimate that there are around 90,000 giraffes left on Earth, he said. That’s a low number already—about a quarter of the number of elephants remaining, and elephants are in decline themselves. And if we can now say that there are four species of giraffes, each genetically distinct from the other and not thought to mate with each other in the wild, then the odds of any one of those species going extinct goes up quite a bit.

“With each of these four giraffe species now numbering less than 35,000, they are in peril of being lost forever by the end of this century,” Cavener says.

The good news is that a better understanding of giraffe genetics can help conservationists determine which species are in the most need of funding. For instance, now that they are recognized as their own species, northern giraffes and reticulated giraffes appear to be in particularly dire straits, with populations of just 4750 and 8700, respectively.

And there’s much work yet to be done. The scientists now want to sample every known population of giraffes in Africa to get an even better understanding of their distribution and genetics. And who knows what they’ll find.

“It’s not entirely impossible that we will find another species,” Janke says.

NUS Environmental Research Institute, Subnero
Researchers in Singapore Deploy Robot Swans to Test Water Quality
NUS Environmental Research Institute, Subnero
NUS Environmental Research Institute, Subnero

There's something peculiar about the new swans floating around reservoirs in Singapore. They drift across the water like normal birds, but upon closer inspection, onlookers will find they're not birds at all: They're cleverly disguised robots designed to test the quality of the city's water.

As Dezeen reports, the high-tech waterfowl, dubbed NUSwan (New Smart Water Assessment Network), are the work of researchers at the National University of Singapore [PDF]. The team invented the devices as a way to tackle the challenges of maintaining an urban water source. "Water bodies are exposed to varying sources of pollutants from urban run-offs and industries," they write in a statement. "Several methods and protocols in monitoring pollutants are already in place. However, the boundaries of extensive assessment for the water bodies are limited by labor intensive and resource exhaustive methods."

By building water assessment technology into a plastic swan, they're able to analyze the quality of the reservoirs cheaply and discreetly. Sensors on the robots' undersides measure factors like dissolved oxygen and chlorophyll levels. The swans wirelessly transmit whatever data they collect to the command center on land, and based on what they send, human pilots can remotely tweak the robots' performance in real time. The hope is that the simple, adaptable technology will allow researchers to take smarter samples and better understand the impact of the reservoir's micro-ecosystem on water quality.

Man placing robotic swan in water.
NUS Environmental Research Institute, Subnero

This isn't the first time humans have used robots disguised as animals as tools for studying nature. Check out this clip from the BBC series Spy in the Wild for an idea of just how realistic these robots can get.

[h/t Dezeen]

There May Be an Ancient Reason Why Your Dog Eats Poop

Dogs aren't known for their picky taste in food, but some pups go beyond the normal trash hunting and start rooting around in poop, whether it be their own or a friend's. Just why dogs exhibit this behavior is a scientific mystery. Only some dogs do it, and researchers aren't quite sure where the impulse comes from. But if your dog is a poop eater, it's nearly impossible to steer them away from their favorite feces.

A new study in the journal Veterinary Medicine and Science, spotted by The Washington Post, presents a new theory for what scientists call "canine conspecific coprophagy," or dogs eating dog poop.

In online surveys about domestic dogs' poop-eating habits completed by thousands of pet owners, the researchers found no link between eating poop and a dog's sex, house training, compulsive behavior, or the style of mothering they received as puppies. However, they did find one common link between the poop eaters. Most tended to eat only poop that was less than two days old. According to their data, 85 percent of poop-eaters only go for the fresh stuff.

That timeline is important because it tracks with the lifespan of parasites. And this led the researchers to the following hypothesis: that eating poop is a holdover behavior from domestic dogs' ancestors, who may have had a decent reason to tuck into their friends' poop.

Since their poop has a high chance of containing intestinal parasites, wolves poop far from their dens. But if a sick wolf doesn't quite make it out of the den in time, they might do their business too close to home. A healthier wolf might eat this poop, but the parasite eggs wouldn't have hatched within the first day or two of the feces being dropped. Thus, the healthy wolf would carry the risk of infection away from the den, depositing the eggs they had consumed away in their own, subsequent bowel movements at an appropriate distance before the eggs had the chance to hatch into larvae and transmit the parasite to the pack.

Domestic dogs may just be enacting this behavior instinctively—only for them, there isn't as much danger of them picking up a parasite at home. However, the theory isn't foolproof. The surveys also found that so-called "greedy eaters" were more likely to eat feces than dogs who aren't quite so intense about food. So yes, it could still be about a poop-loving palate.

But really, it's much more pleasant to think about the behavior as a parasite-protection measure than our best pals foraging for a delicious fecal snack. 

[h/t The Washington Post]


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